And by comparing gas emissions during and between bursts, they found differences in composition indicating that the gas slugs originated at a depth of about 10,000 feet (3,000 meters) beneath the crater.

That is approximately the base of the mountain, where it rests on the seabed.

"The gas phase driving the explosions preserves the memory of hotter—but also deeper—source conditions," the scientists wrote.

Volcano Plumbing

Other scientists studying Stromboli are pleased with the findings.

"It's a nice complement to what seismology can do," said Bernard Chouet, a geophysicist with the U.S. Geological Survey in Menlo Park, California.

Prior research used a network of seismic stations to determine that the conduit feeding the volcano flares wider about 800 feet (250 meters) beneath the surface, Chouet said.

Rather than originating in this region as previously believed, gas slugs rise quietly from below until they reach the area and have more room to expand, the new study suggests.